Hand held band saw

ABSTRACT

A hand held band saw particularly adapted to split animal carcasses. The band saw includes a novel housing structure that permits quick and easy access to the housing&#39;s interior for cleaning of the interior, and for installing a new endless saw blade. The band saw also includes a novel blade guide roller assembly, and a novel blade take-up assembly, which cooperate to permit quick and easy installation of an endless saw blade.

This application is a continuation-in-part application of U.S.application Ser. No. 785,037 filed Apr. 6, 1977, now abandoned, andassigned to the same assignee as this application.

This invention relates to band saws. More particularly, this inventionrelates to a band saw of the hand-held type.

Band saws are very well known to the prior art. Band saws basicallycomprise a continuous or endless length saw blade in a closed loopconfiguration, the blade passing over a driven wheel at one end of theblade's loop and an idler wheel at the other end of the blade's loop.The band saw blade is continuously driven in a single direction aboutthe wheels by the driven wheel, the saw toothed edge of the blade beingexposed to the material to be cut at a mouth defined by the saw'shousing.

Band saws also are known to the prior art in the meat processingindustry. In the meat processing industry, band saws are used forcutting means chuncks or sections in the processing of meat intoconsumer saleable cuts. With particular reference to the hand held bandsaw of this invention, it should be noted that hand held band saws arealso known to the meat processing industry. Generally speaking, a handheld band saw, for purposes of this application, is defined to mean aband saw of the type incorporating an endless saw blade passing over adriven wheel and an idler wheel, the band saw being manipulatable byhand into various spatial cutting orientations even though the saw maybe supported from overhead, e.g., by suspending from a cable or thelike. In other words, a hand held band saw, for purposes of thisapplication, is not deemed to include a band saw of the type used in afixed location, e.g., by mounting on a floor or the like.

As mentioned, hand held band saws are known to the prior art in the meatprocessing industry. Generally speaking, these hand held band saws areused to split or cut up animal carcasses into smaller carcass sections.For example, it is known to split or cut a beef carcass into right andleft hand sections down the backbone of that carcass by means of a handheld band saw. Typical of hand held band saws known to the prior art arethose illustrated and described in U.S. Pat. Nos. 1,374,638, 1,449,805,1,453,335, 1,468,381, 1,512,425, 1,516,529, 2,515,345, 2,596,081,2,604,910 and 3,121,910.

However, the hand held band saws of the prior art which are known toapplicant provide a couple of problems to the operator or user of thehand held band saw. A first problem arises in connection with theremoval of an endless saw blade from the saw's housing, and theinstallation of a new or re-sharpened saw blade with the saw's housing.Such is required when the endless saw blade becomes dull, or when thesaw blade breaks. A second problem arises in connection with cleaningthe structural interior of the hand held saw's housing. The interior ofthe housing, because of the nature of the product being cut when thehand held band saw is used in the meat processing industry, requires aperiodic cleaning to maintain optimum operating cutting characteristicsof the saw, as well as to maintain cleanliness standards established inthat industry. In connection with hand held band saws of commerciallyused prior art structures of which I have knowledge, it is relativelydifficult and time consuming to change to saw blade on those sawsbecause of the relatively complex guide roller and saw blade tensioningapparatus employed. Furthermore, and as to those commercially used priorart hand held hand saws which are acceptable from an operator safetystandpoint, the housing interiors are not readily and easily accessiblefor through cleansing or for blade replacement. In other words, thehousing structures of those hand held band saws which maintain theenclosure integrity required for the housing when the saw is in use (soas to comply with desirable operator safety standards) are relativelydifficult to open or close for cleansing or blade changing purposes.

Accordingly, it has been one objective of this invention to provide animproved hand held band saw that incorporates a novel housing structure,that housing structure permitting ready and easy access to the housing'sinterior for changing of the saw blade or cleansing of that interiorwhile maintaining optimum closure integrity for the housing from anoperator safety stand-point when the saw is in use.

It has been another objective of this invention to provide and improvedhand held band saw structure which incorporates at least one of a novelguide roller assembly system, and a novel blade take-up assembly, whichassembly permits the endless blade of the band saw to be easily andsimply installed, and which permits the tracking of that blade to beeasily and simply adjusted once the blade is installed.

Other objectives and advantages of this invention will be more apparentfrom the following detailed description taken in conjunction with thedrawings in which:

FIG. 1 is a perspective view of an improved band saw;

FIG. 1a is a diagrammatic perspective view illustrating the housingdoors in an open position, the internal parts not being shown;

FIG. 2 is a side elevational view of one side of an improved hand heldband saw in accord with the principles of this invention;

FIG. 3 is a side elevational view of the other side of the improved handheld band saw;

FIG. 4 is a top view thereof;

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 3;

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 3;

FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 3;

FIG. 8 is a partially broken away side elevational view of the drivenwheel end of the hand held band saw as taken from that side illustratingin FIG. 3;

FIG. 9 is a partially broken away side elevational view of the idlerwheel end of the hand held band saw as taken from that side illustratedin FIG. 3;

FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 9;

FIG. 11 is a cross-sectional view taken along line 11--11 of FIG. 9;

FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 8;

FIG. 13 is a cross-sectional view taken along line 13--13 of FIG. 12;

FIG. 14 is a cross-sectional view taken along line 14--14 of FIG. 13;

FIG. 15 is a perspective view of the guide plate;

FIG. 16 is a top view of an alternative alignment roller assembly in theretracted position; and

FIG. 17 is a side view of that alternative assembly but showing thatassembly in the extended position.

GENERAL STRUCTURE

The overall structure of the improved hand held band saw 10 of thisinvention is particularly illustrated in FIGS. 1, 1a, 2, 3 and 4. Asshown in those figures, the improved hand held band saw 10 includes ahousing comprised of a driven wheel housing 11 and an idler wheelhousing 12. The driven wheel housing 11 includes handles 13, 14, one oneach side thereof, for grasping by the operator so as to manuallymanipulate the saw 10 as desired. An endless length saw toothed blade15, i.e., a saw blade in loop configuration, is engaged in frictiondrive relation with driven wheel 16 in the driven wheel housing 11, andis also engaged with idler wheel 17 in the idler wheel housing 12. Theendless saw blade 15 is adapted to be driven by motor 18 in thedirection of arrow 19 as illustrated in the Figures.

The endless saw blade 15 is adapted to cooperate with a trackingassembly within the housing 11, 12, the tracking assembly functioning totranslate the blade into a planar attitude parallel to the medianlongitudinal plane 20 of the housing 11, 12 from the normal bandattitude as the blade traverses throat 21 of the saw 10. That portion ofthe tracking assembly which so translates the blade 15 from the normalband attitude (in which the blade is disposed normal to the housing'smedian plane 20 as shown in FIGS. 5--7) into the cutting attitude (inwhich the band is parallel to the housing's median plane 20) include afirst alignment roller assembly 22 in the driven wheel housing 11 and asecond alignment roller assembly 23 in the idler wheel housing 12. Thetracking assembly also includes a blade take-up assembly 24 and thealignment roller assemblies 22, 23 are adjustable to provide correcttracking of the endless blade 15 over the driven 16 and idler 17 wheelsduring operation of the saw.

In use by an operator, the saw 10 may be connected with an overheadsupport (not shown) by a cable 25 attached to the saw's housing 11, asat 26. The overhead support (not shown) may be in the nature of acounterbalance mechanism (not shown) which aids the operator inmanipulating the saw in an up-and-down direction illustrated by phantomarrow 17. In other words, the overhead support and counterbalanceapparatus serves to reduce the saw's weight from an operator'sstandpoint. The saw 10 is hand manipulatable or orientatable, however,as the operator grips handle 13 with one hand and handle 14 with theother hand, thereby permitting the spatial orientation of the saw to beas desired by the user. With the saw blade 15 continuously running indirection illustrated by arrow 19, and oriented in a generallyhorizontal plane relative to floor level, the saw 10 can be simply moveddown through an animal carcass's backbone in a direction illustrated byphantom arrow 28 from the upper or tail end of that carcass to the loweror shoulder end of that carcass so as to split the carcass into rightand left hand sections as that carcass hangs down from an overheadconveyor.

The Housing

The housing structure of the improved hand held band saw is particularlyillustrated in FIGS. 3--9 and 11. As shown in those Figures, and aspreviously mentioned, the housing structure basically includes a drivenwheel housing 11 and an idler wheel housing 12. The two housings 11, 12are connected by a crossbar section 30. The crossbar section 30 and thetwo end housings 11, 12 cooperate to define the throat area 21 of thesaw through which the endless saw blade 15 runs. Note the blade 15 runsthrough the throat area 21 in an orientation that presents the blade'ssaw toothed edge 29 as the exterior edge of the blade.

The driven wheel housing 11 includes a main housing section 31 and adoor 32, the door being hingedly connected by pin 33 on a hinge axis 34which is perpendicular to the cutting path 19 of the saw blade 15, seeFIGS. 1, 1a and 8. The housing's main section 31 carries the motor 18fixed to that section by bolts 18a. The first handle 13 is mounted onthe casing of motor 18, the handle including a trigger switch 13b bymeans of which motor 18 (and, hence, the saw blade 15) can be activatedby an operator. The pistol grip handle 13 is located in a planegenerally parallel to the median plane 20 of the saw blade's housing 11,12. The second handle 14 is mounted on the outside of the door 32, thathandle being a rod-type handle which extends generally normal to themedian plane 20 of the saw 10. The pistol grip handle 13 is adapted tobe gripped by the right hand of the saw's operator, and the bar handle14 is adapted to be gripped by the left hand of the saw's operator, sothat the saw 10 can be easily manipulated in use into the variousspatial orientations desired. The door 32 is maintained in closurerelation with the main section 31 by door bolt 32b. The door bolt 32b isprovided with a knurled knob 35 on the exterior end thereof, thethreaded end 36 of the bolt being received in a threaded cavity 36 onthe interior face of the main housing's main section 31 so as to providea latch by which the door 32 is kept in closure relation with thehousing's main section.

The exterior of the housing's main section 31 also mounts a connectorbar 38 pivotally connected to that housing section by pin 39, thatpivotal connection being generally located adjacent the center ofgravity of the saw and defining a pivot axis 40 normal to the medianplane 20 of the saw's housing 11, 12. The connector bar 38 is of alength sufficient to extend upwardly beyond the top edge 41 of thehousing's main section 31, and define a hole 42 at the top or free endthereof. A cable hook 25 is receivable in the connector bar's hole 42 tosupport the saw 10 from an overhead support, e.g., a counterbalancemechanism (not shown). The exterior face of the driven wheel housing'smain section 31 also mounts a flush valve 43 having an on/off handle 44,the valve and valve handle being part of a flushing system described ingreater detail hereinafter. The flush valve 43 is provided with aconnector 45 that permits the valve 43 to be connected to a fluid, e.g.,water, source.

The driven wheel housing's interior includes a drive mechanism for theendless saw blade 15. The drive mechanism includes driven wheel 16 whichis bolted, as at 50, to a concentric ring gear 51. The driven wheel 16includes hub 52, that hub 52 being carried on a fixed central shaft 53by bearings 54. The fixed shaft 53 is mounted in the housing's mainsection 31 by structure not shown. A pinion 55, mounted on shaft 56 ofthe motor 18, is engaged with the driven wheel's ring gear 51. Thus, themotor 18, pinion 55 and ring gear 51 thereby serve to rotate or drivethe driven wheel 16 when the motor is activated by trigger switch 13b.

A scraper block 57, preferably fabricated of a polyethylene, is adaptedto bear against the exterior face 58 of the driven wheel 16 on that sideof the wheel which is free of the saw blade 15. The scraper block 57serves to scrape fat and bone dust from the driven wheel 16 during useof the saw in the meat processing industry. The scraper block 57 isfixed to bracket 49, that bracket being mounted to the inside face ofthe housing's main section by bolt 59.

The driven wheel housing's main section mounts a curved guide plate 60on the inside or throat edge 61 thereof in that area of the blade 15entry into that housing 11, see FIGS. 8 and 15. The curved guide plate60 extends or curves outwardly relative to the throat 21 of the band saw10, and is mounted to the housing's main section 31 by bolts 63. Theguide plate 60 includes curved feet 64 that curve outwardly from theinside edge 61 of the driven wheel housing's main section 31 back towardthe bottom edge 65 of that section 31, i.e., that terminate between theend edges 61, 66 of that section 31. The guide plate 60 is comprised oftwo separate or spaced feet 64 that define a slot 68 therebetween, asillustrated in FIG. 15, the saw blade 15 passing through that slot 68.Note particularly that each of the feet 64, in the area adjacent towhere the endless blade 15 passes therebetween, mounts a scraper block69, thereby locating a scraper block on each side of the endless sawblade, see FIGS. 8 and 12. Each block 69 preferably is fabricated ofpolyethylene, and is bolted as at 70 to the guard plate. The scraperblocks serve to prevent chunks of fat or bone dust from passing into theinterior of the driven wheel housing 12 during use. The driven wheelhousing 12 also carries an alignment roller assembly 22 and a bladeflushing pipe 71 interiorly thereof, these structural components beingdescribed in greater detail below.

The idler wheel housing 12 also includes a main section 73 and a door74, the door being hingedly connected by pin 75 on a hinged axis 76which is parallel to the cutting path 19 of the saw blade 15, see FIGS.9 and 11. The main section 73 and the door 74 cooperate, on the bottomedge 77 thereof, to define a V-shaped nose 78 in cross section, note thesolid line of FIG. 11. One half 78a of the V-shaped nose 78 is formedfrom the bottom edge of main section 73, and the other half 78b of thenose 78 is formed from the bottom edge of door 74. In other words, theidler wheel housing 11 is provided with a nose 78 on the throat edge orbottom edge 77 of that housing with main section 73 of the housingdefining a linear portion 78a of that V-shaped nose section, the door 74defining a linear section plus the V-tip as 78b, see FIG. 11. ThisV-shaped nose is an important structural feature of the band saw's idlerwheel housing 11 for the reason that it permits that portion to passthrough an animal carcass without gettting hung up thereon as it mightif that bottom edge 77 were planar. More particularly, the idler wheelhousing's door 74 is connected to the main section 73 by spaced crosslinks or bars 79 to define the horizontal hinge axis 76, each bar beingpivotally pinned as at 75 to main section 73 at one end and fixed byscrews 80 to the door 74 at the other end. This door hinge 79 structurepermits the door 74 to be swung down so that the door half 78b of the Vnose 78 swings under the main section half 78a of the V nose 78 as thedoor is opened. The door 74 is maintained in fixed relation with iderwheel housing's main section 73 by a thumb bolt 82. The thumb bolt 82passes through the door 74 and is threaded on the exterior of thehousing, and the threaded portion is received into collar 83 integralwith the interior face of the main section 73. Knurled head 84 of thebolt 82 permits easy latching and unlatching of the door 74.

The idler wheel housing 12 carries the idler wheel 17 therein. The idlerwheel 17 is mounted on a blade take-up assembly 24 described in greaterdetail below. It is through the take-up assembly 24 that the idler wheel17 is mounted to the main section 73 of the idler wheel housing 12. Theidler wheel housing 12 also mounts an alignment roller assembly 23identical to the alignment roller assembly 22 carried in the drivenwheel housing 11. This alignment roller assembly 23 is likewisedescribed in greater detail below.

The idler wheel housing 12 and the driven wheel housing 11 are connectedtogether one with the other in rigid or fixed relation by the crossbarsection 30 of the saw's housing, see FIGS. 8 and 9. The crossbar section30 is of a structurally rigid nature, and includes channel 85 definedtherein through which the saw blade 15 passes on its return run shown byarrow 86. Note particularly that the crossbar section 30, at the mouthor bottom edge 87 thereof, is also provided with a V-shaped noseconfiguration, see particularly FIG. 6. This V-shaped nose of thecrossbar 30 at the mouth edge 87 thereof permits the crossbar to passdown between, for example, the right half and left half carcass sectionsas the carcass is being split so the saw 10 does not get hung up oneither section. The crossbar 30 is bolted to the driven wheel housing 11by five bolts 88 at one end, and the crossbar is bolted to the idlerwheel housing 12 by four bolts 89 at the other end, thereby rigidly andfixedly connecting the housings 11, 12 and crossbar 30 into a one-piecehousing for the saw 10.

The crossbar 30 is adapted to be covered on that surface 90 whichdefines the channel 85 by a separate cover plate 91, see FIGS. 5-9. Thecover plate 91 is provided with a hole 92 at each end thereof, each holecooperating with a locater pin 93 fixed to the crossbar 30. The coverplate 91 is, thereby, adapted to be located in its assembled position byvirtue of the crossbar's locater pins 93 being received through theholes 92 in the cover plate 91 at each end thereof, see FIGS. 5 and 7.Further, the cover plate 91 is retained in assembled relation with thecrossbar 30 by cooperation of latch structure fixed to the driven wheelhousing's door 32 and to the idler wheel housing's door 74 upon closureof those doors as shown in FIGS. 5 and 7. In other words, the doors 32,74 of the driven wheel housing 11 and the idler wheel housing 12,respectively, also cooperate with the crossbar's cover plate 91 tomaintain that cover plate in assembled relation with the crossbar. Thelatch structure which provides this function includes, on each door 32,74, a pair of threaded studs 94 threaded into the door, the studsextending out beyond the inner face 95 of the door a limited extent, andbeing retained in that extended attitude by set nuts 96. When the doorsare closed, i.e., when the housing is assembled as illustrated in FIGS.1 and 2, the spaced studs 94 on the door overlie and bear against thecover plate 91 for the crossbar 30, thereby retaining same in coveringrelation with the crossbar so as to enclose the band saw blade in thereturn run 86 of that blade through the crossbar. In other words, thedoors 32, 74 overlie the cover plate 91 so as to maintain it in theassembled or closure attitude.

This band saw housing structure completely encloses the band saw blade15 during use of the hand held band saw 10 except, of course, forexposed or cutting run through the mouth 21 of the saw. In other words,the door 32 and main section 31 of the driven wheel housing 11, and thedoor 74 and main section 73 of the idler wheel housing 11, cooperate toenclose totally the saw blade 15 portions within those sections.Further, the cover plate 91 and the crossbar 30 cooperate to enclosefully the return run of the saw blade in the crossbar section of the sawhousing. This is highly desirable from an operator safety standpoint.However, both the driven wheel housing 11, the idler wheel housing 12and the crossbar 30 are easily opened and exposed for cleaning orflushing, or for changing of the blade, simply by unlatching the doors32, 74 of each housing by releasing the thumb bolts 32b, 82. When thethumb bolts 32b, 82 are disengaged, the doors 11, 12 may be pivoted openabout respective pivot axes 34 and 76. With the doors 32, 74 pivotedopen, the doors' studs 94 are released against the cover plate 91 of thecrossbar 30, thereby permitting the cover plate to be simply lifted offthe crossbar so as to expose the blade 15 and the channel 85 defined inthe crossbar. With the interior of the saw housing completely exposed,the housing may be flushed clean by a water hosing or otherwise, or thesaw blade 15 may be easily changed or a new saw blade installed.

The Tracking Assembly

The tracking assembly for the hand held band saw 10 of this invention isparticularly illustrated in FIGS. 8-14. The tracking assembly basicallycomprises a blade take-up structure 24 connecting the idler wheel 17 andthe idler wheel housing 12, an alignment roller assembly 23 in the idlerwheel housing, and an alignment roller assembly 22 in the driven wheelhousing 11.

The blade take-up assembly 24 is primarily illustrated in FIGS. 9 and10. As shown therein, the idler wheel 17 is mounted on a hub 101 bybolts 102. The hub 101 is rotatably carried on shaft 103 by bearings(not shown). The shaft 103 is fixed to a triangular mounting plate 104,that mounting plate being connected by bolts 105 to a slide plate 106.The bolted connection of the mounting plate 104 to the slide plate 106is not structurally rigid, i.e., permits a limited tilting motionbetween the mounting plate 104 and the slide plate 106. In other words,the idler wheel 17 is adapted to tilt or angle relative to the slideplate 106 because the mounting plate 104 to which it is connected isadapted to angle or tilt relative to the slide plate. The slide plate106 includes rails 107 along opposed side edges thereof, those railsbeing slidingly received on ribs 108 defined along the parallel sideedges of hole 109 in the idler wheel housing's main section 73. Thus,the slide plate is adapted to reciprocate or slide in a linear path 110defined by the slide ribs, that path being parallel to the cutting orexposed run 19 of the saw blade 15.

The idler wheel 17 is tiltingly mounted to the slide plate 106 aspreviously noted. The angle or degree of tilt of the idler wheel 17relative to the slide plate 106 is regulated by a first adjustment bolt111 connected to the slide plate, see FIG. 10. As shown in that Figure,the first adjustment bolt 111 is movable in a direction normal to theplane of the slide plate 106, and is adapted to bear against theunconnected point 112 of the idler wheel's triangular mount plate 104 onthe underside thereof. The first adjustment bolt 111 is thereby adaptedto tilt the idler wheel 17 about a tilt axis 113 defined by theconnector bolts 105 that connect the mount plate with the slide plate,see FIG. 9. Further, the slide plate 106 is positionable along slideribs 108 by a second adjustment bolt 114. The second adjustment bolt 114is threadedly connected with collar 115 on the slide plate 106, andpasses through the idler wheel housing's main section 73 with the headend thereof bearing against wall portion 117 of that section 73, seeFIG. 10. Turning of the second adjustment bolt 114 will cause the slideplate 106 to slide toward the outer edge 118 of the idler wheel housing12, thereby tensioning the saw blade 15 between the idler wheel 17 andthe driven wheel 16. The idler wheel 17 is tilted relative to the planeof the slide plate 106 by the first adjustment bolt 111 until an angularposition of that idler wheel relative to the plane of the driven wheel16 is achieved so that, after the blade 15 has been suitably tensionedby second adjustment bolt 114, the saw blade 15 tracks on both wheels16, 17 without running off one or the other.

An alignment roller assembly 22 and 23 is provided in each of the drivewheel housing 11 and the idler wheel housing 12. The alignment rollerassemblies 22, 23 are identical one to the other in both the housings11, 12, the only difference being that the idler wheel roller assembliesare positioned to face toward one another as illustrated in FIG. 1. Thealignment roller assembly 22, 23 is particularly illustrated in FIGS. 8,9, and 12-14. The alignment roller assembly 23 in the idler wheelhousing 12, cooperates to transpose the endless saw blade 15 from areturn run attitude normal to the vertical plane 20 of the drive 16 andidler 17 wheels into a cutting run attitude parallel to that plane, andthe alignment roller assembly 22 cooperates to transpose the endless sawblade from that cutting run attitude parallel to the plane of the idler17 and driven 16 wheels to a return run attitude normal to the verticalplane 20. This transposition of the endless saw blade 15 is, of course,necessary to permit the saw blade to encircle the driven 16 and idler 17wheels in planar relation with the exterior periphery thereof.

As illustrated in FIGS. 12-14, each alignment roller assembly 22, 23includes a set of three rollers 120-122 carried on an L-shaped forkedbracket 123. The blade edge roller 120 is vertically oriented in a planeparallel to the cutting run of the saw blade 15 and to the median plane20 of the saw housing, that roller being adapted to bear againstnon-toothed edge 125 of the blade 15. The edge roller 120 is carried ona stationary shaft 126 by roller bearings 127, that stationary shaftbeing fixed between upright arms 128 of the roller assembly bracket 123,see FIG. 14. Shoulder 129 of the stationary shaft 126 sits againstupright arm 128a of the bracket 123 and nut 130 holds the shaft 126 infixed relation with arm 128b of the bracket, thereby permanentlylocating the edge roller 120 in the desired position relative to thebracket 123.

The edge roller 120 is of generally cup-shaped cross-sectionalconfiguration, the roller bearings 127 being press fit against theinside wall 132 of the roller 120 but spaced from floor 133 of theroller 120 to define a grease cup 134 space between the bearings 127 andfloor 133. The head end of the stationary shaft 126 mounts a greasefitting 135, and the shaft itself defines a grease bore 136 opening atport 137 in the shaft. Note the grease port 137 opens into grease cup134 area, thereby permitting grease to be introduced into the rollerbearings 127 and to maintain a supply of grease for those rollerbearings.

Each alignment roller assembly 22, 23 also includes two coplanar facerollers 121, 122 adapted to bear against the side faces 139 of the blade15. The face rollers 121, 122 are, therefore, in a plane perpendicularto the plane of the edge roller 120. The face rollers 121, 122 arejuxtaposed one adjacent the other, and each is rotatably mounted to aswing arm 140. Each swing arm 140 is pivotally mounted on a side leg 141of the alignment roller assembly's bracket 123 at a toe 142 thereof, thepivot axis 143 so defined being parallel to the plane of the edge roller120. The pivotal connection of each swing arm 140 with a side leg 141 isestablished by bolt 144. An adjustment screw 145 is threaded in each ofthe bracket's legs 141 at the upright arm 128 end thereof, the screw 145being adapted to bear against the outer side edge 146 of the associatedswing arm 140. Turning of the adjustment screws 145 permits the sideface rollers 121, 122 to be forced closer to one another, therebyexerting pressure on the endless blade's side faces 139 which passtherebetween. Note particularly that the rotational axes 147 of the sideface rollers 121, 122 are disposed on a line 148 which is angulatedrelative to the travel path 19 of the blade 15, and relative to theplane 149 of the edge roller 120. This angulation of the side facerollers 121, 122, relative to the edge roller's plane 149, as opposed toorienting those side face rollers on a center line (not shown), that isperpendicular to the edge roller's plane, permits greater twistingpressure to be exerted against the endless blade 15, and, thereby,permits greater control to be exerted over alignment and tracking ofthat blade. The swing arms 140 and adjustment screws 145 permit easy andquick changing of the saw blade 15.

Each side face roller 121, 122, as illustrated in FIG. 13, is providedwith a grease fitting 151 threaded into the top face 152 thereof. Thegrease fitting 151 opens into a grease cup 153 area of the roller, theroller thereby functioning also as a grease cup. The rollers 121, 122are mounted on swing arm 140 by threaded shaft 154, that shaft beingfixed to the swing arm by nut 155. Roller bearings 156 interposedbetween the shaft 154 and the cup-shaped rollers 121, 122 permitrotation of the side face roller about that shaft on the rotational axis147. Thus, the structural configuration of each side face roller 121,122 also is in the form of a cup so as to provide a grease storage area153 with the roller. This structure permits periodic greasing of therollers 121, 122 so as to maintain a free rolling roller bearings 156.

Each roller assembly's bracket 123 is connected or mounted to ahousing's main section 31 or 73 on mounting block 160 as illustrated inFIG. 8 for driven wheel housing 11, or on mounting block 161 asillustrated in FIG. 9 for idler wheel housing 12 by bolt 162. The blocks160, 161 are fixed in place to the housings 11, 12. The connector bolts162 each define a pivot axis 163 in the median plane of the edge roller120. Alignment screws 164 are received in both the housing's mainsections 31, 73, and each screw 164 is adapted to bear against itsassociated bracket 123, as shown in FIG. 13. In proper positioning ofthe alignment rollers 120-122 (and, hence, of the alignment rollerassembly's bracket 123) relative to the blade 15, the alignment screw164 permits fine alignment of that assembly with the blade, i.e.,permits pivoting of that bracket about pivot axis 163, when a new bladeis installed within the housing. Once the proper alignment is achieved,bolt 162 is tightened to fix the guide roller assembly 22, 23 in itsproper position.

An alternative mounting structure 170 for guide roller assembly 22 isillustrated particularly in FIGS. 16 and 17. The mounting structure forguide roller assembly 22 in the FIGS. 8 and 13 embodiment includes block160 permanently fixed to housing section 31, the assembly 22 beingconnected to that block 160 by bolt 162. In other words, and in theFIGS. 8 and 13 embodiment, the guide roller assembly 22 is permanentlyfixed in position relative to the rotational axis of drive wheel 16,although that assembly can pivot on the axis of bolt 162 when the bolt162 is loosened. In the alternative embodiment illustrated in FIGS. 16and 22, the guide roller assembly 22 is movably mounted so that theassembly 22 can be located between an inner position illustrated in FIG.16 and an outer position illustrated in FIG. 17. In this alternativemounting structure 170 for guide wheel assembly 22, the assembly 22 ismovable along a path parallel to the return run 19 of the endless sawblade 15 relative to the drive wheel 16.

The alternative mounting structure 170, as illustrated in FIG. 16,includes a pair of spaced pins 171, 172 permanently fixed to housingsection 31, the pins extending inwardly from the inner face of thathousing section towards the opposite housing section 32. A knurled headthumb screw 173 is received in linear slot 174 defined in housingsection 31, the linear slot being parallel to a center line 175 whichincludes both pins 171, 172, and being spaced above those pins in theside wall of that housing section 31. A mounting bracket 176 for guideroller assembly 22 is cooperatively engaged with the pins 171, 172 andthe thumb screw 173. The mounting bracket 176 includes an upper rail 177and a lower rail 178, those rails being spaced at each end by spacerblocks 179, 180 so as to define linear slot 181 therebetween. Thebracket 176 is received in sliding relation on the pins 171, 172 throughslot 181 in that bracket, and the thumb screw 173 is received in toprail 177 of that bracket in a threaded bore 182 provided therein. Thus,the mounting bracket is movable between an outer position shown in FIG.17 where pin 172 abuts spacer 180, and an inner position shown in FIG.16 where pin 171 abuts spacer 179, and is fixed in the desired positionrelative to the inner and outer limits by thumb screw 173.

The alternative mounting structure 170 also includes a front mountingarm 183 and a rear mounting arm 184 that extend transversely out fromthe mounting rails 177, 178, the arms being connected to the rails byseparate top 185 and bottom 186 bolts. The front mounting arm 183carries guide plate 60 as mounted by bolts 187. Thus, the guide plate60, which is particularly illustrated in FIG. 15 (except for thelocational difference in mounting holes), is also slideable between theextended and retracted positions so as to maintain its spatial relationrelative to the guide roller assembly 22. The guide roller assembly 22is fixed to the rear mounting arm 184 by bolt 188. The guide rollerassembly 22 is of the same structure as illustrated in FIGS. 8 and 12-14except that it is mounted to the sliding guide assembly 170. Thus, theguide roller assembly 22 functions, after being mounted to the slidingguide assembly 170, exactly the same as described above except that itis, as previously mentioned, extendable and retractable relative to thedrive wheel 16.

The sliding guide assembly 170, in combination with the guide rollerassembly 22 and the guide plate 60, has been unexpectedly found toreduce blade 15 breakage during use of the hand held band saw. In thisregard, the sliding guide assembly 170, in combination with drive rollerassembly 22 and guide plate 60, permits throat length T of the saw to beadjusted between maximum and minimum positions as permitted by themounting structure 170 of this alternative embodiment. The throat lengthwith the guide roller assembly 22 and guide plate 60 completelyretracted (as shown in FIG. 16) is big enough for handling the maximumsize animal on which the saw is to be used, and the throat length withthe guide roller assembly 22 and guide plate 60 completely extended (asshown in FIG. 17) is small enough for the minimum sized animals to behandled with the saw. This provides a significant operating advantage tothe band saw in that, when the throat length T is narrowed or widened tothe preferred length for use with a given size animal, the blade is lesslikely to twist while cutting because less free blade is exposed,thereby allowing the operator to provide a straighter cut through theanimal. Further, it has been found desirable to reduce the throat lengthto the minimum possible relative to the animal size being handled so asto provide the maximum distance possible between the guide rollerassembly 22 and the drive wheel 16. This maximum distance between theguide roller assembly 22 and the drive wheel 16 provides a maximumdistance for the blade to twist between its cutting run 19 attitude andits return run 86 attitude as it passes over the drive wheel 16, therebyreducing blade stress and increasing the useful life of the blade. Inother words, it has been unexpectedly found that by maintaining thethroat length T of the band saw at the minimum relative to the size ofthe animal being processed, the blade 15 is less likely to twist duringcutting and the blade life is increased as the twist instance betweenguide roller assembly 22 and drive wheel 16 is increased, therebyproviding two significant advantages to the sliding guide assembly 170.

As previously mentioned, a flush pipe or line 71 is used in connectionwith the hand held band saw 10 of this invention, see FIGS. 2 and 8. Thesingle flush line 71 is connected with water valve 43 at one end. Theflush line 71 terminates in a nozzle 165 oriented to discharge a flow ofwater in a plane that is coplanar to the cutting plane of the endlesssaw blade 15 when that blade is in its cutting run attitude. This nozzle165 is positioned immediately ahead of the side face rollers 121, 122 ofthe alignment roller assembly 22 positioned within the driven wheelhousing 11 and only a single nozzle is used in the driven wheel housing11, and no nozzle is used in the idler wheel housing 12. In other words,the nozzle 165 is positioned upstream of the alignment roller assembly22 relative to the motion path 19 of the saw blade's cutting run. Thus,the water flow discharge from the nozzle 165 flows against top edge 125of the endless blade 15, and flows onto and over the side faces 139thereof to at least partially rinse the blade prior to that blade beingtwisted from the cutting attitude into the tracking attitude, i.e.,prior to that blade passing through the alignment roller assembly 22,within the driven wheel housing 11.

Having described in detail the preferred embodiment of my invention,what I desire to claim and protect by Letters Patent is:
 1. A hand heldband saw comprisinga driven wheel housing, said driven wheel housingincluding a door hingedly mounted thereon, an idler wheel housing, saididler wheel housing including a door hingedly mounted thereon, and acrossbar section, said crossbar section rigidly connecting said drivenwheel housing and said idler wheel housing, said crossbar sectionincluding a cover plate adapted to enclose the return run of an endlesssaw blade therethrough, said cover plate being held in assembled housingrelation with said crossbar section upon closure of said idler wheelhousing door and upon closure of said driven wheel housing door.
 2. Ahand held band saw as set forth in claim 1 wherein said housingstructure includeslocater pins to preliminarily locate said cover platein closure relation with said crossbar section prior to closure of saididler wheel housing's door and said driven wheel housing's door.
 3. Ahand held band saw as set forth in claim 1, said housing structureincludingadjustable pressure means connected to said doors, saidadjustable pressure means permitting said doors to maintain said coverplate in assembled housing relation with said crossbar section.
 4. Ahand held band saw as set forth in claim 1 wherein the axis of saiddriven wheel housing's door is perpendicular to the cutting run of saidband saw's endless saw blade, and wherein the hinge axis of said idlerwheel housing's door is parallel to the cutting run of said band saw'sendless saw blade.
 5. A hand held band saw as set forth in claim 1, saidhousing structure includinga V-shaped nose on the bottom edge of saididler wheel housing, and a V-shaped nose on the mouth edge of saidcrossbar section.
 6. An idler wheel housing for a band saw of the handheld type, said housing comprisinga main section and a door, the loweredge of said door and the lower edge of said main section cooperating todefine a V-shaped nose at the bottom edge of said idler wheel housing,and hinge means connecting said door and said main section, said hingemeans permitting said door to open to expose the interior of said idlerwheel housing.
 7. An idler wheel housing as set forth in claim 6 whereinabout one-half of said V-shaped nose is carried on said main section andabout one-half of said V-shaped nose is carried on said door, the hingeaxis of said door being parallel to the cutting run of said band saw'sendless belt, and includingat least one bar connecting said door andsaid main section, said bar permitting said door to swing down and undersaid main section upon opening of said door.
 8. A tracking assembly foran endless saw blade of a hand held band saw, said tracking assemblyincludinga blade take-up assembly located with said saw's idler wheelhousing, said blade take-up assembly comprisinga slide plate slidablymounted on said idler wheel housing; a mounting plate pivotally mountedto said slide plate, said mounting plate carrying said idler wheel inrotatable relation thereon, a first adjuster connected to said slideplate and adapted to bear against said mounting plate, the position ofsaid first adjuster relative to said slide plate determining the angularposition of said idler wheel relative to said slide plate, and a secondadjuster connected to said slide plate and adapted to bear against saididler wheel housing the position of said second adjuster relative tosaid slide plate determining the position of said idler wheel relativeto a driven wheel of said band saw,and an alignment roller assemblylocated in said band saw idler wheel housing and an idler rollerassembly located in said saw's driven wheel housing, each of saidalignment roller assemblies comprisingan edge roller positioned to bearagainst the non-toothed edge of said endless saw blade, two side facerollers, said side face rollers being disposed to bear against oppositesides of said endless saw blade, the rotational axes of said side facerollers being on a line angulated relative to the plane of said edgeroller, and a swing arm on which is mounted one of said side facerollers, said swing arm permitting said one side face roller to beadjusted relative to the other side face roller.